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 * This code is distributed in the hope that it will be useful, but WITHOUT

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 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

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/*

 *******************************************************************************

 * (C) Copyright IBM Corp. 1996-2005 - All Rights Reserved                     *

 *                                                                             *

 * The original version of this source code and documentation is copyrighted   *

 * and owned by IBM, These materials are provided under terms of a License     *

 * Agreement between IBM and Sun. This technology is protected by multiple     *

 * US and International patents. This notice and attribution to IBM may not    *

 * to removed.                                                                 *

 *******************************************************************************

 */

package java.text;

import sun.text.normalizer.NormalizerBase;

/**

 * This class provides the method {@code normalize} which transforms Unicode

 * text into an equivalent composed or decomposed form, allowing for easier

 * sorting and searching of text.

 * The {@code normalize} method supports the standard normalization forms

 * described in

 * <a href="http://www.unicode.org/unicode/reports/tr15/tr15-23.html">

 * Unicode Standard Annex #15 &mdash; Unicode Normalization Forms</a>.

 * <p>

 * Characters with accents or other adornments can be encoded in

 * several different ways in Unicode.  For example, take the character A-acute.

 * In Unicode, this can be encoded as a single character (the "composed" form):

 *

 * <pre>

 *      U+00C1    LATIN CAPITAL LETTER A WITH ACUTE</pre>

 *

 * or as two separate characters (the "decomposed" form):

 *

 * <pre>

 *      U+0041    LATIN CAPITAL LETTER A

 *      U+0301    COMBINING ACUTE ACCENT</pre>

 *

 * To a user of your program, however, both of these sequences should be

 * treated as the same "user-level" character "A with acute accent".  When you

 * are searching or comparing text, you must ensure that these two sequences are

 * treated as equivalent.  In addition, you must handle characters with more than

 * one accent. Sometimes the order of a character's combining accents is

 * significant, while in other cases accent sequences in different orders are

 * really equivalent.

 * <p>

 * Similarly, the string "ffi" can be encoded as three separate letters:

 *

 * <pre>

 *      U+0066    LATIN SMALL LETTER F

 *      U+0066    LATIN SMALL LETTER F

 *      U+0069    LATIN SMALL LETTER I</pre>

 *

 * or as the single character

 *

 * <pre>

 *      U+FB03    LATIN SMALL LIGATURE FFI</pre>

 *

 * The ffi ligature is not a distinct semantic character, and strictly speaking

 * it shouldn't be in Unicode at all, but it was included for compatibility

 * with existing character sets that already provided it.  The Unicode standard

 * identifies such characters by giving them "compatibility" decompositions

 * into the corresponding semantic characters.  When sorting and searching, you

 * will often want to use these mappings.

 * <p>

 * The {@code normalize} method helps solve these problems by transforming

 * text into the canonical composed and decomposed forms as shown in the first

 * example above. In addition, you can have it perform compatibility

 * decompositions so that you can treat compatibility characters the same as

 * their equivalents.

 * Finally, the {@code normalize} method rearranges accents into the

 * proper canonical order, so that you do not have to worry about accent

 * rearrangement on your own.

 * <p>

 * The W3C generally recommends to exchange texts in NFC.

 * Note also that most legacy character encodings use only precomposed forms and

 * often do not encode any combining marks by themselves. For conversion to such

 * character encodings the Unicode text needs to be normalized to NFC.

 * For more usage examples, see the Unicode Standard Annex.

 *

 * @since 1.6

 */

public final class Normalizer {

   private Normalizer() {};

    /**

     * This enum provides constants of the four Unicode normalization forms

     * that are described in

     * <a href="http://www.unicode.org/unicode/reports/tr15/tr15-23.html">

     * Unicode Standard Annex #15 &mdash; Unicode Normalization Forms</a>

     * and two methods to access them.

     *

     * @since 1.6

     */

    public static enum Form {

        /**

         * Canonical decomposition.

         */

        NFD,

        /**

         * Canonical decomposition, followed by canonical composition.

         */

        NFC,

        /**

         * Compatibility decomposition.

         */

        NFKD,

        /**

         * Compatibility decomposition, followed by canonical composition.

         */

        NFKC

    }

    /**

     * Normalize a sequence of char values.

     * The sequence will be normalized according to the specified normalization

     * from.

     * @param src        The sequence of char values to normalize.

     * @param form       The normalization form; one of

     *                   {@link java.text.Normalizer.Form#NFC},

     *                   {@link java.text.Normalizer.Form#NFD},

     *                   {@link java.text.Normalizer.Form#NFKC},

     *                   {@link java.text.Normalizer.Form#NFKD}

     * @return The normalized String

     * @throws NullPointerException If {@code src} or {@code form}

     * is null.

     */

    public static String normalize(CharSequence src, Form form) {

        return NormalizerBase.normalize(src.toString(), form);

    }

    /**

     * Determines if the given sequence of char values is normalized.

     * @param src        The sequence of char values to be checked.

     * @param form       The normalization form; one of

     *                   {@link java.text.Normalizer.Form#NFC},

     *                   {@link java.text.Normalizer.Form#NFD},

     *                   {@link java.text.Normalizer.Form#NFKC},

     *                   {@link java.text.Normalizer.Form#NFKD}

     * @return true if the sequence of char values is normalized;

     * false otherwise.

     * @throws NullPointerException If {@code src} or {@code form}

     * is null.

     */

    public static boolean isNormalized(CharSequence src, Form form) {

        return NormalizerBase.isNormalized(src.toString(), form);

    }

}